Nm23 genes have been implicated in the control of tumor metastasis. For many types of tumors there is an inverse relationship between the level of nm23 expression and metastatic potential. Transfection of nm23 into highly metastatic cell lines reduces their metastatic potential. Nm23 genes are also thought to be involved in cellular proliferation and differentiation. Nm23 genes encode nucleoside diphosphate kinases (NDP kinases). These enzymes catalyze the phosphorylation of nucleoside diphosphates to triphosphates and are responsible for maintaining nucleoside triphosphate pools. However, the synthesis of nucleoside triphosphates does not appear to explain the role of nm23 in suppressing metastasis. We have found that nm23 protiens have protein and phospholipid kinase activities. We are currently characterizing these kinase activities and determining whether they occur in cells, and if so, whether they are related to the suppression of metastasis. - Biochemistry, Cell signaling, Metastasis, Phosphorylation, Protein Kinase, Secretion, - Neither Human Subjects nor Human Tissues